How Contagious are Tapeworms?


Dr Barchas,

I’ve reviewed your web page on tapeworms and have a few questions. I am fostering a pregnant cat (apps. 1 year old, and about 5 weeks pregant) for a local humane society and found the tapeworm segments about a week ago. The shelter vet tech gave me medicine to give to her to address the problem. My local vet wanted to wait to treat the tapeworm until after the kittens were born.

My questions are: Is the room “contaminated” with the tapeworm parasite? What do you recommend? The foster is kept in a separate room from my other cat. Is the drug safe for a pregnant cat?

Thank you for your assistance!


You started your question by mentioning that you’d already searched my website. That’s a surefire way to get your question to the head of the line.

Tapeworms are common and disgusting intestinal parasites of cats and dogs. However, they are not terribly pathogenic. This means that although they are bad for the health of their hosts, tapeworms rarely cause overt disease.

The most common tapeworm in cats (and dogs) is spread by fleas. The tapeworms are not directly contagious. As long as no fleas infest the cats in the house, the tapeworms should not spread. The key to controlling the problem is to use a good flea preventative in all of the cats who aren’t pregnant . . . and possibly the one who is (more on this below).

Prescription tapeworm treatments are generally pretty safe. So are high quality flea preventatives. However, it is best to avoid medications during pregnancy. In an ideal world, no cat would ever need medicine while pregnant. In your case, one must weigh the risks against the benefits.

The safe use of tapeworm medicines and flea preventatives during pregnancy has not been established. However, neither praziquantel (the most commonly prescribed tapeworm medicine) nor any high quality flea preventative is a documented teratogen (a compound known to affect fetal development). If you use the medicines, the kittens will probably be fine. This is especially true during the last trimester of pregnancy (the last 21 days), which is not that far off.

Try to keep your house flea-free. Use a high quality flea preventative on all of the non pregnant cats in the house. If I were in your situation, I would also apply the same sort of medicine to the pregnant cat. However, you must accept the very remote risk that flea preventatives could cause harm to the kittens.

Likewise, I would treat the pregnant cat for tapeworms. This may (but almost certainly won’t) lead to problems in the kittens. Tapeworms are only mildly pathogenic. But they are pathogenic.

I believe that the benefits of flea and tapeworm treatment outweigh the risks in your situation. But it is not an open-and-shut case.

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